1 /* 2 * sunxi Watchdog Driver 3 * 4 * Copyright (c) 2013 Carlo Caione 5 * 2012 Henrik Nordstrom 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * Based on xen_wdt.c 13 * (c) Copyright 2010 Novell, Inc. 14 */ 15 16 #include <linux/clk.h> 17 #include <linux/err.h> 18 #include <linux/init.h> 19 #include <linux/io.h> 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/moduleparam.h> 23 #include <linux/of.h> 24 #include <linux/platform_device.h> 25 #include <linux/types.h> 26 #include <linux/watchdog.h> 27 28 #define WDT_MAX_TIMEOUT 16 29 #define WDT_MIN_TIMEOUT 1 30 #define WDT_MODE_TIMEOUT(n) ((n) << 3) 31 #define WDT_TIMEOUT_MASK WDT_MODE_TIMEOUT(0x0F) 32 33 #define WDT_CTRL 0x00 34 #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1)) 35 36 #define WDT_MODE 0x04 37 #define WDT_MODE_EN (1 << 0) 38 #define WDT_MODE_RST_EN (1 << 1) 39 40 #define DRV_NAME "sunxi-wdt" 41 #define DRV_VERSION "1.0" 42 43 static bool nowayout = WATCHDOG_NOWAYOUT; 44 static unsigned int timeout = WDT_MAX_TIMEOUT; 45 46 struct sunxi_wdt_dev { 47 struct watchdog_device wdt_dev; 48 void __iomem *wdt_base; 49 }; 50 51 /* 52 * wdt_timeout_map maps the watchdog timer interval value in seconds to 53 * the value of the register WDT_MODE bit 3:6 54 * 55 * [timeout seconds] = register value 56 * 57 */ 58 59 static const int wdt_timeout_map[] = { 60 [1] = 0b0001, /* 1s */ 61 [2] = 0b0010, /* 2s */ 62 [3] = 0b0011, /* 3s */ 63 [4] = 0b0100, /* 4s */ 64 [5] = 0b0101, /* 5s */ 65 [6] = 0b0110, /* 6s */ 66 [8] = 0b0111, /* 8s */ 67 [10] = 0b1000, /* 10s */ 68 [12] = 0b1001, /* 12s */ 69 [14] = 0b1010, /* 14s */ 70 [16] = 0b1011, /* 16s */ 71 }; 72 73 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev) 74 { 75 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 76 void __iomem *wdt_base = sunxi_wdt->wdt_base; 77 78 iowrite32(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL); 79 80 return 0; 81 } 82 83 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev, 84 unsigned int timeout) 85 { 86 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 87 void __iomem *wdt_base = sunxi_wdt->wdt_base; 88 u32 reg; 89 90 if (wdt_timeout_map[timeout] == 0) 91 timeout++; 92 93 sunxi_wdt->wdt_dev.timeout = timeout; 94 95 reg = ioread32(wdt_base + WDT_MODE); 96 reg &= ~WDT_TIMEOUT_MASK; 97 reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[timeout]); 98 iowrite32(reg, wdt_base + WDT_MODE); 99 100 sunxi_wdt_ping(wdt_dev); 101 102 return 0; 103 } 104 105 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev) 106 { 107 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 108 void __iomem *wdt_base = sunxi_wdt->wdt_base; 109 110 iowrite32(0, wdt_base + WDT_MODE); 111 112 return 0; 113 } 114 115 static int sunxi_wdt_start(struct watchdog_device *wdt_dev) 116 { 117 u32 reg; 118 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 119 void __iomem *wdt_base = sunxi_wdt->wdt_base; 120 int ret; 121 122 ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev, 123 sunxi_wdt->wdt_dev.timeout); 124 if (ret < 0) 125 return ret; 126 127 reg = ioread32(wdt_base + WDT_MODE); 128 reg |= (WDT_MODE_RST_EN | WDT_MODE_EN); 129 iowrite32(reg, wdt_base + WDT_MODE); 130 131 return 0; 132 } 133 134 static const struct watchdog_info sunxi_wdt_info = { 135 .identity = DRV_NAME, 136 .options = WDIOF_SETTIMEOUT | 137 WDIOF_KEEPALIVEPING | 138 WDIOF_MAGICCLOSE, 139 }; 140 141 static const struct watchdog_ops sunxi_wdt_ops = { 142 .owner = THIS_MODULE, 143 .start = sunxi_wdt_start, 144 .stop = sunxi_wdt_stop, 145 .ping = sunxi_wdt_ping, 146 .set_timeout = sunxi_wdt_set_timeout, 147 }; 148 149 static int __init sunxi_wdt_probe(struct platform_device *pdev) 150 { 151 struct sunxi_wdt_dev *sunxi_wdt; 152 struct resource *res; 153 int err; 154 155 sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL); 156 if (!sunxi_wdt) 157 return -EINVAL; 158 159 platform_set_drvdata(pdev, sunxi_wdt); 160 161 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 162 sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); 163 if (IS_ERR(sunxi_wdt->wdt_base)) 164 return PTR_ERR(sunxi_wdt->wdt_base); 165 166 sunxi_wdt->wdt_dev.info = &sunxi_wdt_info; 167 sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops; 168 sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; 169 sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; 170 sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; 171 sunxi_wdt->wdt_dev.parent = &pdev->dev; 172 173 watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev); 174 watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout); 175 176 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt); 177 178 sunxi_wdt_stop(&sunxi_wdt->wdt_dev); 179 180 err = watchdog_register_device(&sunxi_wdt->wdt_dev); 181 if (unlikely(err)) 182 return err; 183 184 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", 185 sunxi_wdt->wdt_dev.timeout, nowayout); 186 187 return 0; 188 } 189 190 static int __exit sunxi_wdt_remove(struct platform_device *pdev) 191 { 192 struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev); 193 194 watchdog_unregister_device(&sunxi_wdt->wdt_dev); 195 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL); 196 197 return 0; 198 } 199 200 static void sunxi_wdt_shutdown(struct platform_device *pdev) 201 { 202 struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev); 203 204 sunxi_wdt_stop(&sunxi_wdt->wdt_dev); 205 } 206 207 static const struct of_device_id sunxi_wdt_dt_ids[] = { 208 { .compatible = "allwinner,sun4i-wdt" }, 209 { /* sentinel */ } 210 }; 211 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids); 212 213 static struct platform_driver sunxi_wdt_driver = { 214 .probe = sunxi_wdt_probe, 215 .remove = sunxi_wdt_remove, 216 .shutdown = sunxi_wdt_shutdown, 217 .driver = { 218 .owner = THIS_MODULE, 219 .name = DRV_NAME, 220 .of_match_table = of_match_ptr(sunxi_wdt_dt_ids) 221 }, 222 }; 223 224 module_platform_driver(sunxi_wdt_driver); 225 226 module_param(timeout, uint, 0); 227 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); 228 229 module_param(nowayout, bool, 0); 230 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 231 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 232 233 MODULE_LICENSE("GPL"); 234 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>"); 235 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>"); 236 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver"); 237 MODULE_VERSION(DRV_VERSION); 238